1. Field of the Invention
The present invention relates to a storage system and a data management method. More specifically, the invention relates to technology for backing up or restoring data using an externally connected storage apparatus.
2. Description of Related Art
Conventionally, as external storage apparatuses for replicating data sent from general-purpose computers (called host apparatuses), tape library apparatuses using magnetic tape cartridges, and storage apparatuses using volumes logically defined in a storage area provided by physical disks (hereinafter referred to as logical volumes) are used.
Also, connected between host apparatuses and external storage apparatuses, a virtualization apparatus is used to provide the host apparatuses with logical volumes virtually defined in a storage area provided by physical disks (hereinafter simply referred to as virtual volumes).
Examples of a method for backing up data sent from a host apparatus at high speeds using the above-described apparatuses include the following.
Data sent from a host apparatus is first stored in volumes provided in a virtualization apparatus and logically defined in a storage area provided by physical disks (hereinafter simply referred to as logical volumes). Then, the data stored in the logical volumes is replicated in other logical volumes via backup processing on a per-volume basis. That replicated data for the data is stored in virtual volumes, but actually is stored in logical volumes provided in a storage apparatus connected externally to the virtualization apparatus.
Meanwhile, in the backup processing, in order to protect data and achieve improved reliability, several generations of backup data should be created. In common backup processing, backup data is made in inexpensive tape library apparatuses, i.e., replicated data is transferred from a virtualization apparatus to a tape library apparatus via a backup server, and stored there.
JP11-242570 A discloses techniques for installing a magnetic disk apparatus having magnetic disks and a tape library apparatus in one external storage apparatus, and executing data backup and restoration between the magnetic disk apparatus and the tape library apparatus, enabling the realization of efficient management of data storage capacity and efficient data access.